Low Potency of Indian Dust Mite Allergen Skin Prick Test Extracts Compared to FDA-Approved Extracts: A Double-Blinded Randomized Control Trial

Abstract

Background: Skin prick testing is the most important diagnostic tool to detect immunoglobulin E-mediated allergic diseases. With increase in the number of allergy tests performed in India, it is imperative to know the potency of indigenous extracts in comparison with U.S. Food and Drug Administration (USFDA)-approved extracts. Methods: A randomized comparison trial of Indian manufactured and USFDA-approved extracts of Dermatophagoides pter-onyssinus (DP) and Dermatophagoides farinae (DF) was done at the skin test reactivity of indigenous allergen extracts of dust mites against validated allergen. Study enrollment included 197 patients with allergic disorders that showed sensitivity to dust mite during routine allergy skin testing. Study participants were tested with varying dilutions of DP and DF indigenous extracts along with USFDA-approved allergens in a blinded fashion. Results were recorded, and statistical significance was calculated using the Friedman rank sum test. Results: Using the Friedman rank sum test with a Tukey adjustment for multiple comparisons, we found that the extracts in each dilution were significantly different (P